You need lot's of money to get one of those mate.
I assume you mean the heater for winter when it's parked up, and the cooler for when you go on your jollies to the med.
Storage get a cheapo ceramic heater with frost protection, and tip over switch, someone was flogging a few for around a £10, on here do a search in case he's still got some left.
Hols, there are lots of different ways to provide cooling from evaporative to normal AC, both 12volt and mains.
Kev.